With the Pope and Virgin Mary looking on, he advised pupils on pregnancy and its effects

A large photo of the Pope greeted David Blunkett yesterday as he walked through the gates of Bishop Thomas Grant School in Streatham, south London. The Home Secretary was paying a visit to the Catholic high school to launch a video to help children deal with "challenging issues", such as gun crime.

But yesterday, like a naughty schoolboy caught behind the bike sheds with someone else's girlfriend, the Home Secretary could not escape his own "challenging issues". Every word he uttered seemed to bear a double meaning to his teenage audience.

"I loved being Education Secretary," he told a packed school hall. "It got me into a lot less controversy than being Home Secretary," he declared, to stifled titters from the ranks of uniforms.

Mr Blunkett tried to backtrack. "Let me just clarify," he said, explaining that he was referring to policies and not his tangled private life.

But it was too late. The missdorothy.com resource pack's launch could not even compete with his lurid private life. Even the serious issue of relationship breakdown provoked knowing nudges from a group of teenage girls. "What time is this going to be on the news?" whispered one boy furtively.

Mr Blunkett, whose former mistress, Kimberly Quinn is pregnant with her second child, said it was important to talk to young men about "what happens for instance when their wives or partners or girlfriends get pregnant and the difference that makes to the relationship". Mr Blunkett's minders winced.

The statue of the Virgin Mary, directly behind David Blunkett appeared to adjust her beatific grin. A giant mural of Christ appeared to get brighter and a poster said: "If a relationship makes you feel like running away ... ask for help."

Children wriggled with excitement as TV crews fired questions at the Home Secretary about the affair. A school copper helpfully stepped in to fight back the jostling snappers. But in spite of the mêlée, David Blunkett looked calm. He chatted to some younger children, who seemed to take to him. He whispered to a girl from the Home Office who helped him to his car: "I am sorry you are going to be on the news."

But the head seemed relaxed. "We knew what to expect, in view of the current climate," said Louis Desa, who seems keen on second chances having turned the sink school into a model secondary.

Anyhow, the missdorothy.com resource pack offers some salient advice, should Mr Blunkett need it. "Sometimes we all do things which are wrong. We do not listen to our inner voice," it says. "There are always consequences."